Conventionally, a combination weigher is used to combine objects (e.g., food such as snacks) which are non-uniform in weights to efficiently attain a target weight.
This combination weigher typically includes a dispersion feeder which is capable of dispersing and supplying objects evenly to components around the dispersion feeder, a plurality of linear feeders arranged at equal intervals around the dispersion feeder, feeding hoppers arranged so as to correspond to the linear feeders, respectively, and weighing hoppers arranged so as to correspond to the linear feeders, respectively.
In the above configuration, the objects are sent from the dispersion feeder to linear troughs of the linear feeders, and the objects of a suitable amount are transported by vibration on the linear troughs by vibration components of the linear feeders and fed to the weighing hoppers coupled to load cells through the feeding hoppers, respectively. The load cells detect weights of the objects inside of the weighing hoppers, respectively. Based on a combination of weight values of the weighing hoppers, the weighing hoppers making up an optimal combination in which the weight of the objects falls within a target weight of the objects, are selected. Then, the objects are discharged from the weighing hoppers selected to make up the combination collectively onto a collecting chute located therebelow. A packaging machine packages the collective objects.
The above stated combination weigher is typically used to weigh food as the objects. Therefore, the combination weigher preferably has a sanitary structure. Because of this, components such as the linear troughs, the feeding hoppers, and the weighing hoppers, which the objects directly contact, are formed of, for example, stainless plates. The linear feeders and actuators (motors for opening and closing gates, etc.) are accommodated into, for example, stainless-made cases. This makes it possible to improve a waterproofing property of the linear feeders and the actuators, and suppress entry of foreign matters (wastes of the objects, dust) into the linear feeders and the actuators.
A combination weigher in which the linear feeders and the actuators are accommodated into the cases is shown in FIG. 1 of Patent Literature 1.